Increasing the Number of Chews before Swallowing Reduces Meal Size in Normal-Weight, Overweight, and Obese Adults.

Eating slowly contributes to a lower risk of obesity, probably because it could aid appetite control. Chewing thoroughly is an effective strategy to reduce eating rate; however, insufficient data are available to demonstrate the relationship between such an eating behavior and energy intake. To investigate the effect of increasing the number of chews before swallowing on meal size, a randomized cross-over trial was conducted in 18- to 45-year-old normal-weight, overweight, and obese participants (n=45) who were recruited from the local community (Ames, IA). After assessment of baseline number of chews, participants were asked to attend three test sessions to eat pizza for lunch until comfortably full by chewing each portion of food either 100%, 150%, or 200% of their baseline number of chews before swallowing. Two-way analysis of variance was used to test the effect of treatment and body-weight status, as well as their interactions on food intake, meal duration, eating rate, and appetite at meal termination. Appetite data during 60 minutes were analyzed by repeated measures analysis of variance. Food intake in the sessions with 150% and 200% of their baseline number of chews was reduced significantly, by 9.5% and 14.8%, respectively, compared with the 100% session. Increasing the number of chews also prolonged meal duration and reduced eating rate. However, subjective appetite at meal termination or during the immediate postprandial period did not differ. These data indicate that increasing the number of chews before swallowing might be a behavioral strategy to reduce food intake and potentially aid body-weight management.